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Storm-water diversion, courtesy of a curb

March 13, 2009 |  2:57 pm

Rainwatercurb

Pico and Midvale. Hope and 11th. Venice and Grand. To the average L.A. commuter, these intersections represent nothing but aggravation.

But ask individuals involved with the city's storm-water issues, and these concrete urban crossings are signposts for the future. They're the sites of so-called infiltration planters that divert untreated urban runoff from its one-way trip to the ocean, ushering it instead to landscaping that purifies the water, beautifies the city, replenishes the area's groundwater and reduces the amount of untreated runoff that flows into the ocean.

A natural process called bio-retention, the planters send some of the runoff through notched curbs, where the water feeds landscaping and percolates through the soil. During the wet season, the city of L.A. sends 100 million gallons of runoff every day into the Pacific, where it pollutes the water, negatively affects human and aquatic health and starves the city of a much-needed resource. Even during the dry season, the city pours 10 million gallons of untreated street-borne effluent in the ocean each day. As California heads into its third year of drought and has cut back on water deliveries from its reservoirs, city and county governments, real estate developers and nongovernmental organizations such as Northeast Trees are increasingly turning to infiltration planters to help solve the problem.

"We're looking to weave the textures of nature into our streets and sidewalks because we've learned over the past decade or so that nature has a really elegant solution to pollution," said L.A. City Board of Public Works Commissioner Paula A. Daniels.

Daniels also heads GreenStreets L.A., a program established in 2007 to bring together city agencies and jump-start urban runoff solutions.

"Polluted urban runoff is the No. 1 source of pollution to our ocean, and the types of things that make that water polluted are the kinds of things that plants can actually use as nutrients," Daniels said.

According to a 2007 water augmentation study led by the L.A. and San Gabriel Rivers Watershed Council in partnership with federal, state and local water agencies, none of the oils, fecal matter, heavy metals, chemicals and other storm-water pollutants monitored during a seven-year study of six L.A.-area sites negatively affected the groundwater after filtering through plants and soil.

-- Susan Carpenter

Photo: Don Kelsen / Los Angeles Times

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